Ludwig Institute/UCSD ENCODE project August 2007 Release
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Lindsey Harp
PROVIDER: E-GEOD-8887 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
Similar Datasets
Project description:The readout of genome information is controlled by transcriptional regulatory elements, but a comprehensive view of the combinatorial control by these DNA sequences, which bind regulatory protein and/or the modified histones in regulating gene transcription, is clearly preliminary. We have developed an experimental strategy for comprehensive determination of such functional elements in human DNA. This strategy involves the application of genome-wide location analysis, also known as ChIP-chip, to a panel of well-characterized regulatory proteins and histones with specific modifications, known to generally associate with transcriptional regulatory elements in vivo. Identification of their genomic binding sites will allow us to determine the sequence features in the human genome that carry out transcriptional regulatory function. We have designed and produced DNA microarrays to represent all the non-repetitive sequences in the 30 million basepair ENCODE regions of the human genome to map various types of transcriptional regulatory elements in three model cell types. We have identified promoters by mapping the genomic sequences associated with RNA polymerase II and the general transcription factor TFIID in cells, enhancer elements by mapping the genomic sequences associated with transcriptional co-activators and enhancer-specific chromatin modifications, and insulators by mapping the genomic sequences associated with the insulator binding protein CTCF. The raw microarray results are released periodically prior to publication. Keywords: ChIP-chip ENCODE ChIP-chip analyses were performed for various transcription factors and chromatin modifications in various cell types. Details to be described in publications.
2010-06-12 | E-GEOD-7118 | biostudies-arrayexpress
Project description:The readout of genome information is controlled by transcriptional regulatory elements, but a comprehensive view of the combinatorial control by these DNA sequences, which bind regulatory protein and/or the modified histones in regulating gene transcription, is clearly preliminary. We have developed an experimental strategy for comprehensive determination of such functional elements in human DNA. This strategy involves the application of genome-wide location analysis, also known as ChIP-chip, to a panel of well-characterized regulatory proteins and histones with specific modifications, known to generally associate with transcriptional regulatory elements in vivo. Identification of their genomic binding sites will allow us to determine the sequence features in the human genome that carry out transcriptional regulatory function. We have designed and produced DNA microarrays to represent all the non-repetitive sequences in the 30 million basepair ENCODE regions of the human genome to map various types of transcriptional regulatory elements in three model cell types. We have identified promoters by mapping the genomic sequences associated with RNA polymerase II and the general transcription factor TFIID in cells, enhancer elements by mapping the genomic sequences associated with transcriptional co-activators and enhancer-specific chromatin modifications, and insulators by mapping the genomic sequences associated with the insulator binding protein CTCF. The raw microarray results are released periodically prior to publication. Keywords: ChIP-chip ENCODE ChIP-chip analyses were performed for various transcription factors and chromatin modifications in various cell types. Details to be described in publications. Ren B, Glass CK, Rosenfeld MG, Webster N, Ching KA, Harp L, Ye Z, Stuart RK, Calcar SV, Kim TH, Hawkins RD, Hon G, Barrera LO, Luna R, Wang K
2007-06-01 | E-GEOD-7872 | biostudies-arrayexpress
Project description:The existence of two separate lineages of Escherichia coli O157:H7 has previously been reported, and research indicates that one of these lineages (lineage I) might be more pathogenic towards human hosts. We have previously shown that the more pathogenic lineage expresses higher levels of Shiga toxin 2 (Stx2) than the non-pathogenic lineage II. To evaluate why lineage 2 isolates do not express appreciable levels of toxin, two lineage 2 isolates (FRIK966 and FRIK2000) were chosen as representatives of lineage 2 and whole genome microarrays were performed using Agilent microarrays using the E. coli O157:H7 EDL933 lineage I clinical type isolate as a reference. Microarray results were utilized to evaluate what genes and pathways might be missing or differentially expressed. Quantitative RT-PCR was utilized to validate the microarray data. Based upon the transcriptome of Escherichia coli O157:H7 EDL933 an oligonucleotide microarray, made up of 60 mers was designed. A total of 4873 genes in an 8 x 15K Agilent microarray design. Designed using a custom script, specifications for gene specific oligos were based upon various design characteristics such as temperature of melting, 3’ location, specificity, lack of repeat nucleotides, etc. (Charbonnier et al., 2005). Arrays were manufactured using Agilent Sure-print technology. Each array consisted of duplicate elements for each gene randomly distributed with Agilent control elements included. All procedures were performed according to respective manufacturer protocols. Lineage I and lineage II strains were grown overnight as described, a total of 10e7 cells were washed twice in fresh media, normalized based upon optical density, inoculated into fresh media, incubated at 37oC shaking 120 x g for 3 hours and then suspended in RNAprotect bacteria reagent (Qiagen Inc., Valencia, CA.). Total RNA was extracted using RNeasy Bacteria Mini Kit (Qiagen Inc., Valencia, CA.) and trace amounts of DNA were removed using RNase-Free DNase Set (Qiagen Inc., Valencia, CA.). RNA was quantified using Nanodrop system (NanoDrop Technologies, Wilmington, DE) and quality confirmed by electrophoresis on a Bio-rad Experion system (BioRad XXX). For each sample, 10 ug of RNA were labeled with either CyDye3-dCTP or CyDye5-dCTP (Perkin Elmer) using the LabelStar kit (Qiagen Inc., Valencia, CA.) and Random nonamers (Integrated DNA Technologies ). Labeled cDNA were hybridized to the microarray using Agilent Hi-RPM hybridization solution in an Agilent Hybridization chamber (Agilent.). A total of 8 arrays, each with duplicate elements for each gene, alternating dye swap for each replicate (4 biological replicates), were analyzed to obtain genes that were consistently and differentially regulated in comparison to EDL933, while limiting false discover rate (FDR) below a stringent 5% (Benjamini and Hochberg, 1995).
2009-08-31 | E-GEOD-17070 | biostudies-arrayexpress
Project description:Anopheles gambiae mosquitoes exhibit an endophilic, nocturnal blood feeding behavior. Despite the importance of light as a regulator of malaria transmission, our knowledge on the molecular interactions between environmental cues, the circadian oscillators and the host seeking and feeding systems of the Anopheles mosquitoes is limited. In the present study, we show that the blood feeding behavior of mosquitoes is under circadian control and can be modulated by light pulses, both in a clock dependent and in an independent manner. Short light pulses (~2-5 min) in the dark phase can inhibit the blood-feeding propensity of mosquitoes momentarily in a clock independent manner, while longer durations of light stimulation (~1-2 h) can induce a phase advance in blood-feeding propensity in a clock dependent manner. The temporary feeding inhibition after short light pulses may reflect a masking effect of light, an unknown mechanism which is known to superimpose on the true circadian regulation. Nonetheless, the shorter light pulses resulted in the differential regulation of a variety of genes including those implicated in the circadian control, suggesting that light induced masking effects also involve clock components. Light pulses (both short and longer) also regulated genes implicated in feeding as well as different physiological processes like metabolism, transport, immunity and protease digestions. RNAi-mediated gene silencing assays of the light pulse regulated circadian factors timeless, cryptochrome and three takeout homologues significantly up-regulated the mosquito's blood-feeding propensity. In contrast, gene silencing of light pulse regulated olfactory factors down-regulated the mosquito's propensity to Our study suggests that the mosquitoâs feeding behavior is under circadian control. Long and short light pulses can induce inhibition of blood-feeding through circadian and unknown mechanisms, respectively, that involve chemosensory factors. A series of assays were performed to assess transcriptomic changes in mosquitoes upon light stimulation and blood feeding in order to assess relationships between photic stimulation and modulation of feeding behavior.
2010-06-24 | E-GEOD-13560 | biostudies-arrayexpress
Project description:The complete genome sequence of the P. vivax Sal-1 strain allowed the design of a first version array representing 1 oligo/2 kb of coding sequences (http://zblab.sbs.ntu.edu.sg/vivax/index.html). Here, proof-of-principle experiments using total RNA of parasites obtained from the Sal-1 strain, from P. falciparum and from parasites obtained directly from two human patients are presented. To determine the extent of cross-hybridization of P. falciparum with P. vivax, and to determine overlaps in expression profiles of the P. vivax Sal1 monkey-adapted strain vs wild isolates, single dual hybridization analyses were performed.
2008-04-12 | E-GEOD-11075 | biostudies-arrayexpress
Project description:Background: The mosquito Anopheles gambiae is a major vector of human malaria. Increasing evidence indicates that blood cells (hemocytes) comprise an essential arm of the mosquito innate immune response against both bacteria and malaria parasites. To further characterize the role of hemocytes in mosquito immunity, we undertook the first genome-wide transcriptomic analyses of adult female An. gambiae hemocytes following infection by two species of bacteria and a malaria parasite. Results: We identified 4047 genes expressed in hemocytes, using An. gambiae genome-wide microarrays. While 279 transcripts were significantly enriched in hemocytes relative to whole adult female mosquitoes, 959 transcripts exhibited immune challenge-related regulation. The global transcriptomic responses of hemocytes to challenge with different species of bacteria and/or different stages of malaria parasite infection revealed discrete, minimally overlapping, pathogen-specific signatures of infection-responsive gene expression; 105 of these represented putative immunity-related genes including anti-Plasmodium factors. Of particular interest was the specific co-regulation of various members of the Imd and JNK immune signaling pathways during malaria parasite invasion of the mosquito midgut epithelium. Conclusion: Our genome-wide transcriptomic analysis of adult mosquito hemocytes reveals pathogen-specific signatures of gene regulation and identifies several novel candidate genes for future functional studies. In order to identify hemocyte-specific and immune-responsive transcripts, we first compared transcripts expressed in hemocytes from one day old sugar-fed mosquitoes to transcripts detected in whole mosquitoes of the same age and feeding status. This resulted in identification of the hemocyte-enriched transcriptome. We then compared hemocytes from 1 day old mosquitoes, 1 hour after immune challenge with heat-killed Escherichia coli or Micrococcus luteus, to control female mosquitoes injected with sterile PBS to determine the bacteria challenge responsive transcriptomes. We used heat-killed bacteria in these assays, because our primary interest was in identifying the bacterial responsive transcriptome and to avoid the potentially confounding effects of altered gene expression due to the lethal effects of a systemic infection associated with injection of living bacteria. Lastly, we compared hemocytes from mosquitoes at 24 hours and 19 days after ingestion of a blood meal infected with Plasmodium berghei to mosquitoes of the same age fed a non-infected blood meal to determine the ookinete and sporozoite infection responsive transcriptomes, respectively. This design resulted in a total of five experimental treatments. The following samples are not included in this submission: Hemo E coli vs. hemo unchallenged A Hemo E coli vs. hemo unchallenged B Hemo m luteus vs. hemo unchallenged A Hemo m luteus vs. hemo unchallenged B
2011-10-31 | E-GEOD-33269 | biostudies-arrayexpress
Project description:Background. The bacterial foodborne pathogen Campylobacter jejuni is a common cause of acute gastroenteritis and is also associated with the postinfectious neuropathies, Guillain-Barré and Miller Fisher syndromes. This study described the use of multilocus sequence typing and DNA microarrays to examine the genetic content of a collection of South African C. jejuni strains, recovered from patients with enteritis, Guillain-Barré or Miller Fisher syndromes. Methodology/Principal Findings. The comparative genomic analysis by using multilocus sequence typing and DNA microarrays demonstrated that the South African strains with Penner heat-stable (HS) serotype HS:41 were clearly distinct from the other South African strains. Further analysis of the DNA microarray data demonstrated that the serotype HS:41 strains from South African GBS and enteritis patients are highly similar in gene content. Interestingly, the South African HS:41 strains were distinct in gene content when compared to serotype HS:41 strains from other geographical locations due to the presence of genomic islands, referred to as Campylobacter jejuni integrated elements. Only the genomic integrated element CJIE1, a Campylobacter Mu-like prophage, was present in the South African HS:41 strains whereas absent in the closely-related HS:41 strains from Mexico. A more distantly-related HS:41 strain from Canada possessed both genomic integrated elements CJIE1 and CJIE2. Conclusion/Significance. These findings demonstrated that these C. jejuni integrated elements may contribute to the differentiation of closely-related C. jejuni strains. In addition, the presence of bacteriophage-related genes in CJIE1 may probably contribute to increasing the genomic diversity of these C. jejuni strains. This comparative genomic analysis of the foodborne pathogen C. jejuni provides fundamental information that potentially could lead to improved methods for analyzing the epidemiology of disease outbreaks and their sources. The genomic diversity of 33 South African, 2 Mexican and 1 Canadian Campylobacter jejuni strains from humans were examined by microarray-based comparative genomic indexing (CGI) analysis. The CGI analysis allowed the assessment of CDS content for each C. jejuni strain relative to the C. jejuni DNA microarray, which comprises ORFs from strains NCTC 11168, RM1221. ORFs were spotted in duplicate. Genomic DNA from strains NCTC 11168/RM1221 were used as a reference DNA and competitively hybridized with genomic DNA from each of the other C. jejuni strains. Two or three replicates for each strain were performed. Data normalization was performed as in Parker et al. J Clin Microbiol 2006, 44(11):4125-4135.
2010-05-27 | E-GEOD-9862 | biostudies-arrayexpress
Project description:The local background was subtracted from the fluorescent value of each spot. Feature intensities were extracted from scanned microarray images using GenePix Pro 5.1. (Axon Instruments). The images were visually inspected, and spots from low-quality areas of the array were flagged and excluded from further analysis. Spots were also excluded from analysis if both the combined fluorescent intensity for both channels was less than 1.4 times that of the local background and the pixel-by-pixel correlation coefficient of the spot was less than 0.4. The fluorescence ratios were normalized as previously described (Turton and Gant oncogene 2001website). A hierarchical clustering algorithm (M. Eisen Brown and Botstein PNAS 98 website) was applied to those genes that fulfilled all of the following conditions: they were not flagged; they were differentially expressed (equal or higher than 1.5 fold upregulated or equal or lower than 2 fold downregulated); they had p-values equal or less than 0.02; and they were consistent on at least 4 out of the 5 arrays.
2010-05-27 | E-GEOD-2069 | biostudies-arrayexpress
Project description:Fetal lung development is a complex biological process, which involves temporal and spatial regulations of many genes. To understand molecular mechanisms of this process, we investigated gene expression profiling of lungs at gestational day 18, 19, 20, 21, new born, and adult rats using in-house rat DNA microarray containing 6,000 known genes and 4,000 ESTs. 1,512 genes passed SAM test and 583 genes (402 known genes and 181 ESTs) had a 2-fold change at least at one time point. K-means cluster analysis revealed 7 major expression patterns. Furthermore, using GeneMapp, we identified 3 regulatory pathways: TGF beta signaling pathway, cell cycle, and G-protein signaling; and 2 metabolism pathways: proteasome degradation and glycolysis. Our results suggest a complex regulatory pathway for fetal lung development. Loop Design as following: D18-D19-D20-D21-NB-AD-D18
2010-07-01 | E-GEOD-3302 | biostudies-arrayexpress
Project description:We have designed a zebrafish genomic microarray to identify DNA-protein interactions in the proximal promoter regions of over 11,000 zebrafish genes. Using these microarrays, together with chromatin immunoprecipitation with an antibody directed against tri-methylated lysine 4 of Histone H3, we demonstrate the feasibility of this method in zebrafish. This approach will allow investigators to determine the genomic binding locations of DNA interacting proteins during development and expedite the assembly of the genetic networks that regulate embryogenesis. Genomic array design Microarrays were designed as described below and manufactured by Agilent Technologies (www.agilent.com). Further information on design can be found at http://jura.wi.mit.edu/bioc/gbell/zfish_chip/. Selection of transcription start sites and identification of promoter sequences We interrogated 5 databases: Ensembl, VEGA, Refseq, ZGC full length clones and a database provided by Dr. Leonard Zon (Harvard Medical School, Boston, USA) in order to assemble an extensive list of zebrafish transcripts. The Zon lab database is a hand-curated database of zebrafish genes that have homologues in other species. We included all transcripts that appeared in the manually annotated databases (VEGA, Zon) and in the ZGC full length database. We also identified genes present in any 2 of the 5 databases and included those not already selected. The transcripts were mapped to the zebrafish genome (Zv4, June 2004) obtained from UCSC Bioinformatics (http://genome.ucsc.edu) and the transcription start site (TSS) for each transcript was determined. Transcripts with TSSs within 500bp were clustered into a transcriptional unit (TU) and promoter regions were identified relative to the most upstream TSS. This resulted in the identification of 13,413 TUs and corresponding promoter regions. Each promoter region was extracted and masked for repetitive sequence by RepeatMasker. If the promoter region contained a gap the upstream sequence was also masked. Information on the transcriptional units that were included in the final design can be found at http://jura.wi.mit.edu/bioc/gbell/zfish_chip/. Selection of oligonucleotides 60-mer oligonucleotide probes representing the region between 1.5kb upstream and 0.5kb downstream of the annotated TSS of each transcriptional unit were then designed. Although transcription factors and other DNA binding proteins are known to regulate genes from distances of greater than -1.5kb or + 0.5kb, much information can be gained from regions close to the TSS [45], and the H3K4Me3 mark studied in this paper is found at the most 5â end of a gene, close to the TSS. Selection of 60-mers for the microarrays was essentially as described in [14] using the Zv4 build of the zebrafish genome and a locally customized version of ArrayOligoSelector. 60-mers were chosen so that promoter regions contained approximately one probe every 250bp with a maximum distance between probes for each promoter region set at 600bp. In cases where only one probe could be designed for a particular TU these were not included in the final design. This process yielded 80,839 probes for 11,171 promoter regions We also incorporated several sets of control probes, both positive and negative. On each array there are 1090 probes designed against âgene desertâ regions, which are genomic regions that are unlikely to be bound by transcriptional regulators, and 270 probes designed against Arabidopsis thaliana genes, which are not present in the zebrafish genome (by BLAST). In addition, because our main motivation for making these microarrays is to identify mesodermally-regulated genes we included 7 genes expressed in mesoderm during gastrulation as positive controls (wnt11, flh, vent, msgn1, myod, fgf8, pcdh8). Probes designed against these promoters, which flank from 3-4kb around each TSS, are arrayed 2-4 times on each slide. Since these genes are expressed at gastrula stages to varying degrees, they also serve as a positive controls in this study. Finally there are 2256 controls added by Agilent and a variable number of blank spots. These probes were divided between two microarray slides each with 44,290 features. We refer to these two microarray slides as the âproximal promoter setâ. A proximal promoter set based on these designs as well as an expanded set of 9 slides which contain regions from â9kb to + 3kb relative to the TSS, are available by contacting Agilent (www.agilent.com) or by downloading the design files from http://jura.wi.mit.edu/bioc/gbell/zfish_chip/ for self-manufacture.
2010-07-01 | E-GEOD-4863 | biostudies-arrayexpress